Radar systems are useful for detecting, characterizing, and monitoring various kinematic parameters associated with natural and/or man-made objects and are critical to both civilian and military operations. Active radar systems typically transmit “beams” or electromagnetic (EM) signals intended to engage one or more objects or targets, and process reflected return signals (or echoes) for measuring spatial features, as well as for performing object identification, characterization, and tracking operations. Likewise, passive radar systems may perform similar identification and tracking functions. Their receivers rely on the reflection of EM emissions originating from existing sources, or “emitters of opportunity”. For example, the wide-spread use of TV and radio antennas, cellular phone towers and the like provide an abundant source of EM emitter signals that can be used to aid in the detection and tracking of targets (e.g., airborne targets).
Current passive radar systems generally utilize only a single emitter of opportunity and a single sensor (i.e., a single radar receiver) for tracking targets. The use of all available emitters of opportunity, in conjunction with multiple sensors or receivers, has the potential to provide substantial improvement in tracking performance, particularly when sensors include adaptive antenna arrays. This type of implementation, however, can lead to prohibitively complex systems.
Accordingly, improved systems and methods for tracking objects of interest using a passive radar system are desired.